Magnetic Resonance Imaging
Volume 27, Issue 9 , Pages 1249-1257, November 2009

3D sensitivity encoded ellipsoidal MR spectroscopic imaging of gliomas at 3T☆

  • Esin Ozturk-Isik

      Affiliations

    • Margaret Hart Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA 94158, USA
    • Corresponding Author InformationCorresponding author. Surbeck Laboratory of Advanced Imaging, San Francisco, CA 94143-2532, USA.
    • ,
  • Albert P. Chen

      Affiliations

    • Margaret Hart Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA 94158, USA
    • ,
  • Jason C. Crane

      Affiliations

    • Margaret Hart Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA 94158, USA
    • ,
  • Wei Bian

      Affiliations

    • Margaret Hart Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA 94158, USA
    • ,
  • Duan Xu

      Affiliations

    • Margaret Hart Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA 94158, USA
    • ,
  • Eric T. Han

      Affiliations

    • GE Healthcare, ASL West, Menlo Park, CA 94025, USA
    • ,
  • Susan M. Chang

      Affiliations

    • Department of Neurological Surgery, University of California, San Francisco, CA 94143, USA
    • ,
  • Daniel B. Vigneron

      Affiliations

    • Margaret Hart Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA 94158, USA
    • UCSF/UCB Joint Graduate Group in Bioengineering, San Francisco, CA 94158, USA
    • Program in Bioengineering, University of California, San Francisco, CA 94158, USA
    • ,
  • Sarah J. Nelson

      Affiliations

    • Margaret Hart Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA 94158, USA
    • UCSF/UCB Joint Graduate Group in Bioengineering, San Francisco, CA 94158, USA
    • Program in Bioengineering, University of California, San Francisco, CA 94158, USA

Received 20 July 2008; received in revised form 4 April 2009; accepted 7 May 2009. published online 22 September 2009.

Abstract 

Purpose

The goal of this study was to implement time efficient data acquisition and reconstruction methods for 3D magnetic resonance spectroscopic imaging (MRSI) of gliomas at a field strength of 3T using parallel imaging techniques.

Methods

The point spread functions, signal to noise ratio (SNR), spatial resolution, metabolite intensity distributions and Cho:NAA ratio of 3D ellipsoidal, 3D sensitivity encoding (SENSE) and 3D combined ellipsoidal and SENSE (e-SENSE) k-space sampling schemes were compared with conventional k-space data acquisition methods.

Results

The 3D SENSE and e-SENSE methods resulted in similar spectral patterns as the conventional MRSI methods. The Cho:NAA ratios were highly correlated (P<.05 for SENSE and P<.001 for e-SENSE) with the ellipsoidal method and all methods exhibited significantly different spectral patterns in tumor regions compared to normal appearing white matter. The geometry factors ranged between 1.2 and 1.3 for both the SENSE and e-SENSE spectra. When corrected for these factors and for differences in data acquisition times, the empirical SNRs were similar to values expected based upon theoretical grounds. The effective spatial resolution of the SENSE spectra was estimated to be same as the corresponding fully sampled k-space data, while the spectra acquired with ellipsoidal and e-SENSE k-space samplings were estimated to have a 2.36–2.47-fold loss in spatial resolution due to the differences in their point spread functions.

Conclusion

The 3D SENSE method retained the same spatial resolution as full k-space sampling but with a 4-fold reduction in scan time and an acquisition time of 9.28 min. The 3D e-SENSE method had a similar spatial resolution as the corresponding ellipsoidal sampling with a scan time of 4:36 min. Both parallel imaging methods provided clinically interpretable spectra with volumetric coverage and adequate SNR for evaluating Cho, Cr and NAA.

Keywords: Glioma, 3D MR spectroscopic imaging, SENSE, Ellipsoidal sampling, Brain

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☆ This research was presented in part at the 14th and 15th Annual Conferences of International Society of Magnetic Resonance in Medicine. It was funded by NIH grants P50 CA97257, RO1 CA59880 and a grant jointly funded by the UC Discovery Program (LSIT 01-10107) and GE Healthcare.

PII: S0730-725X(09)00114-3

doi:10.1016/j.mri.2009.05.028

Magnetic Resonance Imaging
Volume 27, Issue 9 , Pages 1249-1257, November 2009

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